Fusible control for manually adjustable devices



April 1940. s. w. RUSHMORE 2 1 ,621

FUSIBLE CONTROL FOR MANUALLY ADJUSTABLE DEVICES Original Filed April 11, 1938 3 Sheets-Sheet 1 m V v/V/ ///7 7/// 7 77?? 5 Q W Zw INVENTOR Jamaal Wifas/mre a ATTRNEY April 16, 1940. s. w. RUSHMORE 2,197,621 FUSIBLE CONTROL FOR MANUALLY ADJUSTABLE DEVICES Original Filed April 11, 1938 3 Sheets-Sheet 2 INVENTOR Jamaei llffiashmore April 1940- s. w. RUSHMORE 2,197,621

FUSIBLE CONTROL FQR MANUALLY ADJUSTABLE DEVICES Original Filed April 11, 1938 3 Sheets-Sheet 3 INVENTOR JmaeZlIffiasfim/e.

ATTORNEY Patented Apr. Iii, 1%40 airman FUSIBLE CONTROL FOR. MANUALLY ADJUSTABLE DEVICES Samuel W. Rushmore, Plainfield, N. J.

Application April 11, 1938, Serial No. 201,325

Renewed June 20, 1939 15 Claims. (01. 123 -108) 7 My present invention is shown as embodied in means for limiting or modifying the opening movement of throttles for internal combustion engines; particularly for those of the motor- 5 vehicle type; and, more specifically, to means for int'erposing substantial or complete resistance to opening the throttle beyond a'predetermined limit, thereby to prevent racing the en-- gine until it is warmed and lubricated sumit ciently to prevent undue wear on pistons and cylinders.

ing or preventing movement of other manually adjustable control devices, where it is desired 1 to have their range of adjustment dependent on the temperature of the device controlled thereby.

For such purposes, I employ as a temperaturesensitive, resistance-varying element, a body of fusible material contained in a receptacle which ii? is in heat receiving relation to a portion of the engine in which temperature variations during the warming-up period, correspond roughly with the cylinder wall and lubricant temperatures,

This fusible material has a melting point iii such that it is normally a solid operating to obstruct and limit the movement of the throttle during the warming-up period, but when sufficiently heated by warming up of the engine, it

will melt and permit maximum movement of the 30 controller.

The fusible material may operate either directly or through a stop element having one portion submerged in said fusible material, and another portion extending into operative relation as for obstructing a movable element of the throttle controls.

For the specific purpose of controlling the throttle of an automobile engine, I prefer to arrange the fusible material in close heat transfer 40 relation with the cooling water in the head jacket of the engine. The fusible material may be cadmium-tin-lead bismuth alloy, these alloys being available in proportions affording solidification points anywhere-between, say, 133 F.

,5 and 203 F. Alloys including this range are specified in Smithsonian physical tables. (See, for instance, 2nd reprint of 7th revised edition, published 1923 by the Smithsonian Institution.) Obviously, however, there are other fusible ma- 50 terials, produced since 1923, which are now on the market, and may be even more useful for.

my purposes.

The fusible material of the desired melting point may be located in a pocket in or secured 55 to the outer wall of the head jacket.

But it will be obvious that certain features of my invention are applicable to limit- When used as an attachment, it may be simply a container or tank brazed or otherwise secured in intimate contact with the exterior vertical wall of the head *jacket. Because of its high heat conductivity, copper is a suitable metal for such container or tank.

The throttle obstructing device may be a plunger which, when the fusible material is melted, is non-positively urged upward to its operative relation with the throttle control elem ments. This may be accomplished by having the submerged portion of the plunger made of a material which is of much less specific gravity than the fusible material. In the case of the alloys above referredto, a solid or hollow alumi num float may serve the purpose, such alloys in liquid state being approximately 3 times the weight of an equal volume of solid aluminum, and the ratio is not much less for certain solid aluminum alloys or mixtures that may be emp-loyed. A spring may be employed to urge the plunger upward. Where the plunger is a float, the spring willsupplement flotation; and where the spring is submerged in the fusible material, the plunger need not be a float.

The-above and other features of my invention may be more readily understood from the following' description in connection with the accom-- panying drawings, in which Fig.1-is aside elevation, partly in vertical section, showing my invention as applied to the throttle "of a downflow intake for an internal combustion engine;

Fig. 2 is a detail section on the line 2--2 of Fig. 1; 1 showing a form wherein the fusible 3o metalcavity and the float are cylindrical;

Fig. 3 is a similar section on line 2--2, Fig. 1, but showing the fioat and cavity as oblong in stead of circular;

Fig. 4 is a view like Fig. 1, but showing a 40 modification;

Fig. 5 is a detail section on line 5-5, Fig. l;

Fig. '6 is a vertical section of a fusible metal container located'as in Fig. 4, but having the stop for the throttle, in the form of a laterally flexible spring that has fixed anchorage in the bottom of the container for fusible metal; and

.Fig. 7 is a view like Fig. l, but showing a third modification.

In Fig. 1, the downflow intake I is throttled by butterfly valve 2, controlled by lever 3.

The variable resistance stop for limiting initial opening of the throttle includes the receptacle Acontaining the fusible metal 5, in which is submerged the float 6, supporting the vertically slidable stop element 7. The receptacle 4 is in intimate heat transfer relation with the water cooled head jacket lb, of the engine. A stifi spring 8 projects radially from and rotates with the throttle control. In this particular form of the device, the spring 8 is backed by a rigid lever 9. When the throttle valve 2 is rotated to open it, the backing lever 9 and spring 8, swing downward, as a unit through a short are, a; whereupon the part of the spring 8 which projects beyond the backing lever 9, engages the stop I. When the engine is cold the float is solidly frozen in the fusible metal 5, thereby preventing further downward movement of the stop, but the throttle may be freely adjusted throughout the relatively short are a After the engine has been warmedup enough to melt the fusible metal 5, the stop may be forced downward by the spring 8 through the further are I), in which extreme lower position the throttle valve 2 is wide open, and the float 6 is deeply submerged.

Thus the backing lever 9 and the free end of the spring 8 are in effect a unitary cam element designed to be positively stopped by stop I, until the motor is warmed up, and to force the stop 1 downward as soon as the fusible metal 5 is heated enough to melt.

The tip of the spring 3 will be more yieldable if the spring is not secured to the backing lever 9 except at the end nearest the throttle.

As shown in Fig. 2, receptacle 4 has a broad base of engagement with the head jacket l0, so'

as to readily absorb heat therefrom; and, as noted above, it may be of copper because copper has extremely high heat conducting quality.

As shown in Fig. 3, the float may be oblong,

instead of circular, and if made of light material, such as aluminum, it may be solid instead of hollow. In this connection, it may be noted that the fusible material can never get much above the boiling point of water, and there are many float materials, lighter than aluminum,

that will safely withstand such temperatures.

In the modification shown in Fig. l, the same or similar parts are identified by the numerals used for Figs. 1 and 2, but withdistinguishing exponents. In this 4, the downtake 1a,

throttle valve 2a, operating lever 3a, and water cooled engine Illa, may be the same as in Fig. 1. The radial arm to which rotates with the throttle, may be like that shown in, Fig. 1, ,ex-,

cept that it does not have the curved tip extending beyond the point of engagement with the stop lb, because its radial length, needbe only suflicient to ensure safe initial engagement with the upper end of said stop 7b. For this and other reasons, I prefer to make the radial arm to, a spring which is very stiff so that the rigid backing arm 9 is not necessary. With this arrangement, the throttle is initially free to swing the spring to down to contact with stop 1b, during the warming up period. During this period, the stop lb; is prevented from any vertical movement, by the solid freezing of the float 6a, in

the fusible metal 5a, contained in receptacle 4b. It will be noted, however, that the stop 1b, while in vertical alignment with its float-supported shank la, is formed with an intermediate curve lc, whereby all the shank is outside the path traversed by the tip end of the spring 8a; and only the extreme upper stop end. lb, lies in said path. i

In order to get full advantage of this curve I To between stop lb and shank la, it is desirable to prevent the stop rod from rotating about its vertical axis, out of the position shown in Fig. 4; and this may be accomplished either by making the float 6a oblong, as in Fig. 3, or by giving the stop la a rectangular cross section as shown in Fig. 5.

When the motor is hot and the fusible metal liquefied, the float Ba automatically positions itself against the stop projections 4d, 412, in which position the shank la is vertical; so when the throttle is opened and the spring 811 comes in contact with the upper stop end lb, it encounters practically no resistance because, first, the float is easily depressed, second, the float can tilt to the left thereby causing la to swing to the right, by'pivoting about the bearing surface at ie, and, third, the shank la is itself slightly flexible and very little camming pressure toward the right will flex it partly or wholly out of the path of the throttle control spring 8a. In other words, the tip lb operates as an easily-yielding, automatically self-restoring detent that affords no appreciable resistance to any movement of the throttle between tight closed and wide open positions.

During the warming up period, while the motor is cold and the float is frozen in the fusible metal, opening the throttle will cause spring 8a to apply thrust directly downward on stop lb, and the stiffness of the spring may be selected,

so that it can apply any desired resistance t0 tip of 8a to snap downward past 1b to positionv where it can straighten out, with its tip in rearward curve lc, where said tip will be entirely out of contact with 10 and-la, all the way to wide open throttle. In case of such intentional violent opening of the throttle by the operator, he can race the engine, knowing that he is doing so, but when he releases the throttle, the spring 8a can bend reversely, and again cam shank 1a outwardly, enough so that the tip of 8a can spring past stop 7a, and so automatically return to theinitial, closed-throttle, position.

In this Fig. 4 I have shown alight spiral spring 80 submerged in the fusible metal 5a resting on the bottom of the receptacle 4b and applying upward thrust on the float 6a, but this is mainly for the purpose of showing how such a submerged spring may be used as a supplement to or a substitute for the float effect required for restoring the stop to initial operative position, while the fusible metal is liquid, before it freezes. The point is that upward thrust applied by this or any other submerged spring, is like flotation, in that the spring becomes anchored, when the fusible metal freezes, the same as a float does.

There are many other ways of utilizing fusible material as means for anchoring a stop when said material is frozen, yet have the stop easily displaceable when the metal is melted.

Fig. 6 shows a very simple form in which the stop is simply a long, flat spring, that has its lower end seated on the bottom of a very naryielding. The spring has its lower two-thirds 1x submerged in the fusible metal 5m in receptacle ire; and its upper third ly projects above the receptacle into position for engagement by the spring liar that controls the throttle. When the fusible metal is frozen, the submerged two-thirds la: is inflexible andtheupper third 11/ is relatively stiff, but when the fusible metal melts, the entire spring caneasily flex about the bearing edge ly as fulcrum, thereby pivoting the upper end out of the path of the end of throttle spring Thrust to cause such pivoting, can only be applied by bending upward the end of throttle spring its, so that it will apply an outward camming effect. Hence spring '83: must be flexible enough to bend easily.

It is not necessary to have the opening movement of the throttle limited by a member that is normally in and held by the fusible metal, when it freezes. For instance, in Fig. 7 the downdraft intake to, throttle valve 20, operating lever 30, correspond with similar parts in Figs. 1 and l; also the receptacle lr, fusible metal 40, fulcrum point 53 and water cooled engine head ills are in a general way like those shown in Fig l. The thrust member if corresponds in a general way with the stop I in Fig. 1, except in this-case it is pivoted to and is carried by the radius arm 80, instead of being supported by float or by spring. i

The operation is very simple. In the position shown. in full lines, the thrust member if has its lower end a predetermined distance above the surface of the fusible metal to. When this metal is rozen, the throttle is free to open until the lower end lg comes in contact with the frozen surface of the metal. Adjustment between these two points is entirely free for variation during the warming up period. When the engine gets hot enough so that the fusible metal melts, the lower end lg of the thrust member can penetrate the fused metal freely, and to any depth, the thrust member if pivoting about the fulcrum edges dc, to the various positions shown in dotted lines. I r

it will be noted that I have referred to my temperature-sensitive, resistance-varying element as having solidification and fusing points such that it remains a solid during warming up temperatures; but melts at warmed up temperatures. In this connection, it will be understood as concerns metal alloys usable for my purpose, that their fusing temperatures and solidification temperatures are not necessarily the same; and, in certain cases, there may be a range of varying mushy or viscous conditions, in which the material is not a solid or a liquid. in the strict sense of those terms. Furthermore, my invention includes other fusible materials which are much less rigid than metals, such as the more solid bitumens; or even materials which are not normally either completely rigid or completely fluid within the range of temperatures at which they normally operate in my apparatus, provided they possess a sufficiently wide range of viscosity within said temperature range.

I claim:

1. A variable-speed, heat-generating mechanism and an adjustable speed-controlling device therefor having a member moving by and in accordance with the adjusting movements thereof, in combination with a body of normally solid fusible material arranged to limit accelerating adjustment of said control member; and also to receive heat from an element having temperature variations corresponding to the internal temperature variations of said variable-speed mechanism; said fusible material having solidification and fusing points such that it remains a solid, obstructing and limiting accelerating movementof said control member during warming up temperatures of said mechanism; but melts at warmed-up temperatures, thereby permitting movement of said control member throughout its normal range of adjustment.

2. Apparatus as specified in claim 1 and in which. there is an intermediate thrust member through which the normally solid fusible material obstructs the movement of the movable,

member of thespeed controlling device.

3. Apparatus as specified in claim 1 and in which there is an intermediate thrust member, having one portion always submerged in the fusible material so as to be frozen therein and thereby anchored with an unsubmerged portion thereof in position to serve as a stop to obstruct and limit accelerating movement of the control member, l

4. Apparatus as specified in claim 1 and wherein'there is an intermediate thrust member supported by a submerged portion which floats in the fusible material when it is melted, and is rigidly supported by said-material when it freezes;

5. Apparatus as specified in claim 1 and where'- in there is an intermediate thrust member pivoted to an arm rotating with the throttle and having its lower end arranged to be lifted a predetermined distance above the surface of the fus icle material, when the throttle is in the closed position, so that when frozen the upper surface of said material operates as a solid stop for said thrust member.

6. A variable speed internal combustion engine and a throttle-valve with adjustable control means for varying the speed of the engine, in combination with a body of normally solid fusible 'material arranged to limit accelerating adjustment of said control means and also to receive heat from a portion of said engine having temperature variations corresponding to the internal temperatures of said engine; said fusible material having solidification and fusing points such that it remains a solid, obstructing and limiting accelerating movement of said control means during warming up temperatures of said mechanism; but melts at warmed-up temperatures, thereby permitting movement of said control means throughout'the normal range of adjustment of said throttle valve.

.7. A variable-speed internal combustion engine and a rotary throttle valve with control means for rotating it to vary the speed of the engine, in combination with a body of normally solid fusible metal arranged to limit accelerating adjustment of said control means and also to receive heat from a portion of said engine having temperature variations corresponding to the internal temperature of saidengine; said fusible metal having solidification and fusing points such that it remains a solid, obstructing and limiting rotary movement of said control means during warming up temperatures of said mechanism; but melts at warmed-up temperatures, thereby permitting rotation of said throttle valve throughout its normal range of adjustment.

8. Apparatus as specified in claim '7 and in which there is an intermediate thrust member through which the normally solid fusible metal obstructs the movement of a movable member of the adjustable means for controlling the throttle.

9. Apparatus as specified in claim 7 and in which there is an intermediate thrust member, having one portion always submerged in the fusible metal so as to be frozen therein and thereby anchored with an unsubmerged portion thereof in position to serve as a stop to obstruct and limit throttle-opening movement of the adjustable control'means. 1

10. Apparatus as specified in claim 7 and wherein there is an intermediate thrust member supported by a submerged portion which floats in the fusible metal when it is melted, and is rigidly supported by said metal when it freezes.

11. Apparatus as specified in claim 7 and wherein there is an intermediate thrust member supported by a submerged portion which floats in the fusible metal when it is melted, and is rigidly supported by said metal when it freezes; saidsubmerged float portion being substantially aluminum and said fusible metal being an alloy which is of much greater specific gravity than the float.

12. Apparatus as specified in claim 1 and wherein there is an intermediate thrust member pivoted to an arm rotating with the throttle and having its lower end a predetermined distance above the surface of the fusible metal, when the throttle is in the closed position, so that when frozen the upper surface of said fusible metal operates as a solid stop for said thrust member.

13. A heat generating device and an adjustable device for controlling the supply of heat generating medium to said heat generating device, said controlling device having a member moving by and in accordance with the adjusting movements thereof, in combination with a body of normally solid fusible material arranged to limit the initial movements of said controlling device and located in heat receiving relation to an element having temperature variations correspond- 7 ing to the internal temperatures of said heat generating device; said fusible material having solidification and fusing points such that it remains a solid, obstructing and limiting the initial movement of said control device during warming up temperatures of said heat generating device;

but melts at warmed-up temperatures thereby permitting movement of said control member throughout its normal range-of adjustment.

14. An internal combustion engine and a manually operated throttle adapted to control the speed of the engine, in combination with means thermo-responsive to the temperature of the engine, arranged to impede movement of the throttle so that the throttle cannot be operated to run the engine at high speeds while the engine is warming up to safe working temperature, except by conscious and unusual effort of the operator.

15. An internal combustion engine and a manually operated throttle adapted to control the speed of .the engine, in combination with means including a thermo-responsive device in heat receiving relation to an element having temperature variations corresponding to the internal temperatures of said engine, and in position to modify the range of free opening of the throttle; said device having a wide temperature-responsive range such that during Warming up of the engine, it affords resistance requiring conscious and unusual effort of the operator to overcome it; but at warmed-up temperatures, decreasing resistance to permit relatively free movement of the throttle throughout its normal range of adjustment.

16. An internal combustion engine and a manually operated throttle adapted to control the speed of the engine, in combination with a body of material having normally high viscosity, located in heat receiving relation to an element having temperature variations corresponding to the internal temperatures of said engine, and in position to limit the range of free opening of the throttle; said material having a wide temperature-viscosity range such that it remains highly viscous; affording substantial resistance to opening of the throttle during warming up temperatures of the engine; but at warmed-up temperatures, having low viscosity to permit relatively free movement of the throttle throughout its normal range of adjustment.

SAMUEL W. RUSHMORE. 

